The final flight for NASA's
2012 Operation IceBridge was also one of the mission's most
important, with a long-awaited survey over sea ice in
Antarctica's Weddell Sea.

On the morning of Nov. 7, the weather in the Weddell Sea was the
best that had been seen during the entire campaign, but clouds
made for a sometimes difficult survey, according to a NASA
statement. Even so, IceBridge's flight successfully intersected
an orbit by the European Space Agency's ice-monitoring satellite,
CryoSat-2, with the satellite passing 450 miles (720 kilometers)
overhead. Data from CryoSat-2 and IceBridge's radar altimeter
will be used to calibrate and validate satellite measurements.

IceBridge is a six-year campaign to survey and monitor areas of
Earth's polar ice sheets, glaciers and sea ice and how they
are responding to climate change. IceBridge fills the gap between
the defunct ICESat satellite and the planned ICESat-2, scheduled
to launch in 2016. Scientists use the mission's instrument-laden
DC-8 to survey areas previously flown in 2009, 2010 and 2011,
which will allow for a year-to-year comparison, as well as new
regions.

"It's an ongoing effort that's really valuable," said Kirsty
Tinto, a geophysicist at Columbia University's Lamont-Doherty
Earth Institute. "It's not just one successful season, it's the
cumulative benefit of the successive seasons of the changing
ice," she told OurAmazingPlanet. Tinto investigates the
interactions between rock, seawater and ice, which influence
how fast glaciers melt when they meet the sea.

The Nov. 7 flight brings the total number of science flights to
16 for the year. The research team spent 215 hours in the air and
flew 81,189 nautical miles (150,362 km), which is more than three
trips around the Earth.

The flights covered the Antarctic Peninsula, Bellingshausen and
Amundsen seas, West Antarctic ice sheet, Weddell Sea, Ronne and
Filchner ice shelves and a portion of the East Antarctic ice
sheet. The scientists also returned twice to
Pine Island Glacier, where a prominent rift may soon release
a giant iceberg.

The 11-hour flights present an unparalleled opportunity for
scientists to see Antarctica with their own eyes as the survey
instruments tick away. "To actually be there and take notes and
time stamp it to the data really makes an enormous difference,"
Tinto said. "There was one high-altitude flight where you could
see the whole system, and really conceptualize what was going
on."